This invention relates to an energy source and more particularly to a separate charging device for generating electrical energy which is to be applied to a dosimeter for subsequent use in measuring local radiation.
Electrometer type dosimeters are well known. Such apparatus, however, requires charging to predetermined value prior to being used. Thereafter when the dosimeter is exposed to surrounding radiation, the electrometer begins to discharge because of the effects of the radiation. The extent to which the electrometer is discharged provides a measure of the amount of radiation sensed by the instrument. After the dosimeter has been sufficiently discharged either from radioactivity or after an extended period of non-use, it must be recharged before being used again.
While integrated battery operated and friction type chargers are known, piezoelectric means for charging a radiation meter is disclosed in U.S. Pat. No. 2,898,472, which issued to H. E. Hollmann on Aug. 4, 1959. There two configurations are disclosed. In each instance a piezoelectric crystal element receives an impact force imparted thereto from another member which causes an internal stress to be produced within the crystal causing the required charging potential to be produced.
It is an object of the present invention, therefore, to provide a separate piezoelectric type dosimeter charger which can be used to charge various types of existing dosimeters.
It is another object of the present invention to provide a charger of the type described which can be used with dosimeters made by different manufacturers for different ranges and which have different barrel sizes and different charging switches.
It is still another object of the present invention to provide a dosimeter charger apparatus which can be used in relatively low light levels; and
Still a further object of the present invention is to provide an improved dosimeter charger which is relatively inexpensive and can be left on a shelf in an inactive state for long periods of time without detrimental effects.